Class: SDN::Client

Inherits:
Object
  • Object
show all
Defined in:
lib/sdn/client.rb

Constant Summary collapse

WAIT_TIME = 
0.25

Instance Method Summary collapse

Constructor Details

#initialize(port) ⇒ Client

Returns a new instance of Client.



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# File 'lib/sdn/client.rb', line 5

def initialize(port)
  uri = URI.parse(port)
  @io = if uri.scheme == "tcp"
    require 'socket'
    TCPSocket.new(uri.host, uri.port)
  elsif uri.scheme == "telnet" || uri.scheme == "rfc2217"
    require 'net/telnet/rfc2217'
    Net::Telnet::RFC2217.new(host: uri.host,
     port: uri.port || 23,
     baud: 4800,
     data_bits: 8,
     parity: :odd,
     stop_bits: 1)
  elsif port == "/dev/ptmx"
    require 'pty'
    io, slave = PTY.open
    puts "Slave PTY available at #{slave.path}"
    io
  else
    require 'ccutrer-serialport'
    CCutrer::SerialPort.new(port, baud: 4800, data_bits: 8, parity: :odd, stop_bits: 1)
  end
  @buffer = ""
end

Instance Method Details

#ensure(message) ⇒ Object 



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# File 'lib/sdn/client.rb', line 40

def ensure(message)
  loop do
    messages = transact(message)
    next if messages.empty?
    next unless message.class.expected_response?(messages.first)
    return messages.first
  end
end

#receive(timeout = nil) ⇒ Object 



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# File 'lib/sdn/client.rb', line 51

def receive(timeout = nil)
  messages = []

  loop do
    message, bytes_read = Message.parse(@buffer.bytes)
    # discard how much we read
    @buffer = @buffer[bytes_read..-1] if bytes_read
    unless message
      break unless messages.empty?

      # one EOF is just serial ports saying they have no data;
      # several EOFs in a row is the file is dead and gone
      eofs = 0
      begin
        block = @io.read_nonblock(64 * 1024)
        SDN.logger.debug "read #{block.unpack("H*").first.gsub(/\h{2}/, "\\0 ")}"
        @buffer.concat(block)
        next
      rescue IO::WaitReadable, EOFError => e
        if e.is_a?(EOFError)
          eofs += 1
        else
          eofs = 0
        end
        raise if eofs == 5

        wait = @buffer.empty? ? timeout : WAIT_TIME
        if @io.wait_readable(wait).nil?
          # timed out; just discard everything
          SDN.logger.debug "discarding #{@buffer.unpack("H*").first.gsub(/\h{2}/, "\\0 ")} due to timeout"
          @buffer = ""
          return messages if timeout
        end

        retry
      end
      next
    end
    if block_given?
      yield message
    else
      messages << message
    end
  end

  messages
end

#send(message) ⇒ Object 



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# File 'lib/sdn/client.rb', line 30

def send(message)
  @io.write(message.serialize)
end

#transact(message) ⇒ Object 



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# File 'lib/sdn/client.rb', line 34

def transact(message)
  message.ack_requested = true
  send(message)
  receive(1)
end